BROKEN slate from the slate quarries is put into a mortar run by steam, and pounded into small particles. Thence it goes into the hopper of a mill, which runs into a "bolting machine," such as are used in flouring mills, where it is "bolted." 

The fine, almost impalpable flour that results is taken to a mixing tub, where a small quantity of steatite flour, similarly manufactured, is added, together with other materials, and the whole is made into a stiff dough.

This dough is kneaded thoroughly by passing it several times between iron rollers. Thence it is conveyed to a table where it is made into "charges," that is, short cylinders, four or five inches thick, and containing eight to twelve pounds each. Four of these are placed in a strong iron chamber, or "retort," with a changeable nozzle so as to regulate the size of the pencil, and subjected to tremendous hydraulic pressure, under which the composition is pushed through the nozzle in a long cord, like a slender snake sliding out of a hole, and passes over a sloping table slit at right angles with the cords to give passage to a knife which cuts them into lengths.

They are then laid on boards to dry, and after a few hours are removed to sheets of corrugated zinc. The corrugation serves to prevent the pencils from warping during the process of baking, to which they are next subjected in a kiln, into which superheated steam is introduced in pipes, the temperature being regulated according to the requirements of the articles exposed to its influence.

From the kiln the articles go to the finishing and packing room, where the ends are thrust for a second under rapidly revolving emery wheels, and withdrawn neatly and smoothly pointed, ready for use. 

They are then packed in pasteboard boxes, each containing one hundred pencils, and these boxes are in turn packed for shipment in wooden boxes, containing one hundred each, or ten thousand pencils. 

Nearly all the work is done by boys, and the cost, therefore, is light.